The present invention relates to a bed, and particularly to a chair bed that can be manipulated to achieve both a conventional bed position having a horizontal sleeping surface upon which a person lies in a supine position and a sitting position having the feet of the person on or adjacent to the floor and the head and back of the person supported above a seat formed by the bed. More particularly, the present invention relates to a hospital bed or a patient-care bed which is convertible to a chair and which is configured to facilitate several activities that may be performed by a caregiver for a person on the sleeping surface of the bed.
Many hospital beds are positionable to a configuration having the sleeping surface of the bed at a predetermined height above the floor and having siderails positioned to restrain the movement of a person lying on the sleeping surface past sides of the sleeping surface and off of the bed. The sleeping surfaces of many such hospital beds can typically be lowered to reduce the distance between the sleeping surface and the floor, and the sleeping surfaces of such beds can often be manipulated to adjust the position of the person on the sleeping surface. In addition, the siderails of these hospital beds can typically be moved to a position away from the sleeping surface to facilitate movement of the person on the sleeping surface from the supine position on the sleeping surface to a standing position on the floor near the bed.
It may sometimes be desirable to have two caregivers assist a person trying to move from the supine position on the sleeping surface of such hospital bed to the standing position. After moving the siderails away from the sleeping surface, the caregivers may pivot the person so that the legs of the person hang over the side of the sleeping surface. The caregivers can then assist the person as the person slides past one side of the sleeping surface until the feet of the person touch the floor. The caregivers typically hold the person firmly while also bracing themselves to prevent a fall or other injury to the person as the person stands.
Beds and examination tables having articulating decks to adjust the position of the person on the surface are known in the art. See, for example, U.S. Pat. No. 5,077,843 to Foster L. Dale et al. and U.S. Pat. No. 4,751,754 to Baily et al., which are assigned to the assignee of the present invention, and U.S. Pat. No. 3,281,141 to Smiley et al. and German publication No. 716981. Each of these references discloses a bed or an examination table having a top surface that articulates to adjust the position of the person on the surface.
In addition, beds and examination tables that are convertible to chairs in order to simplify the task of moving a person on the sleeping surface from the supine position to the standing position are known in the art. See, for example, U.S. Pat. No. 5,157,800 to Borders, U.S. Pat. No. 5,129,177 to Celestina et al., and U.S. Pat. No. 4,862,529 to Peck, all of which are assigned to the assignee of the present invention, and U.S. Pat. No. 5,279,010 to Ferrand et al., U.S. Pat. No. 4,183,109 to Howell, U.S. Pat. No. 4,411,035 to Fenwick, and U.S. Pat. No. 3,220,022 to Nelson. Each of these references discloses a bed that can be converted to a chair-like configuration.
What is needed is a bed that can be converted to a chair and that can also facilitate activities that are typically performed by caregivers. For example, caregivers would welcome a bed that, in addition to being convertible to a chair, can be configured to weigh a person, to rapidly move the person from an upright position to a generally horizontal position when emergency procedures are initiated, and that can facilitate varied procedures that may be performed on a person carried by the bed, thereby reducing the number of times the person is transferred from one bed or surface to another.
According to the present invention, a chair bed for a person is provided, the bed having a head end, a foot end, and sides. The bed includes a base frame, an intermediate frame coupled to the base frame, a weigh frame coupled to the intermediate frame, and an articulating deck coupled to the weigh frame. A plurality of load cell supports couple the weigh frame to the intermediate frame. The load cell supports include means for determining the weight of objects supported by the weigh frame. Alternatively, the weigh frame and the intermediate frame may be fixed together to form a common frame or may be replaced by a single common frame.
In preferred embodiments, the articulating deck has longitudinally spaced head, seat, thigh, and foot sections. The head, thigh, and foot sections are movable relative to each other and are movable relative to the seat section which is fixed relative to the weigh frame. The head, thigh, and foot sections are infinitely adjustable to allow the bed to attain any desired position within the range of movement of the head, thigh, and foot sections, thus accommodating changes of position of a person on the bed. Of course, the articulating deck can provide a planar, horizontal sleeping surface, a planar sleeping surface that is tilted toward either the head end of the bed or the foot end of the bed, and a non-planar chair-shaped seating surface, in addition to the intermediate positions therebetween.
The bed can include a mechanism for raising and lowering the articulating deck and the sleeping surface between a low position and a raised position relative to the base of the bed. In addition, the bed can also include mechanisms for independently raising and lowering each of the head section, the thigh section, and the foot section so that the bed can assume many positions to suit the specific needs of individuals.
The sleeping surface of the chair bed can also be easily moved between a generally horizontal position and a Trendelenburg position. When in the Trendelenburg position, the intermediate frame is tilted such that the head end of the sleeping surface is higher than the foot end. The sleeping surface can also be moved to a reverse Trendelenburg position having the foot end above the head end.
The power required to raise and lower the sleeping surface and to move the head, thigh, and foot sections can be provided by a primary electrical power source such as the main AC power supply of a hospital in combination with a fluid system. In addition, a foot pedal can be pivotably mounted to the base frame and coupled to the bed to allow the caregiver to manually provide power to the bed for remote operation of the fluid system of the bed.
In one preferred embodiment of the bed, the articulating deck and the mechanism for raising and lowering the articulating deck are powered by a fluid system having a pump, valves, and actuators for positioning the intermediate frame relative to the base frame and for positioning the articulating deck sections. The actuators must be supplied with pressurized fluid to manipulate the bed and the valves control the flow of fluid to the actuators.
The bed is additionally provided with an electrical control system for operating a pump and controlling control valves. The electrical control system controls the operation of the bed when the bed is connected to an independent source of power. In addition, the electrical control system includes a battery source for operating the valves when the bed is not connected to an independent source of power.
The articulating deck can be a longitudinal step deck that includes upper deck side portions and a central, longitudinally extending recess between the side portions. The recess is defined by a lower deck and side walls connecting the lower deck and the upper portion of the deck.
A companion mattress is carried by the deck. The mattress has a planar, upwardly-facing sleeping surface, side portions resting on the side deck portions, and a projection beneath the sleeping surface. The projection extends downwardly into the recess and can engage at least a portion of the side wall of the deck. The varied thickness of the mattress provides the mattress with “zones” including a thick zone adjacent to the projection and a thin zone in areas away from the projection. The mattress includes a head mattress portion, a seat mattress portion, a thigh mattress portion, and a foot mattress portion. Each named mattress portion is associated respectively with the head, seat, thighs, and feet of the person resting on the sleeping surface of the bed as well as with the underlying head, seat, thigh, and foot sections of the deck.
A step deck and a mattress configured for use with a step deck can be used independently of the bed and the articulating deck. For example, a step deck can be provided for a stretcher. Such a stretcher, for example, can include a frame, a step deck mounted to the frame, the step deck having longitudinal upper side portions engaging the frame, and a mattress having a generally planar sleeping surface and a bottom surface including a projection configured so that the shape of the bottom surface generally conforms to the shape of the step deck. In the same manner, a step deck and associated mattress could be provided for a gurney. Such a gurney would be similar to the illustrative stretcher described above except that the frame would include wheels so that the gurney could be transported by rolling it from place to place.
Though there are many potential variations of step deck shapes and corresponding mattress shapes and numbers and types of mattress pieces that could be devised, any step deck having an upper deck portion and a recess defined by a bottom deck portion and walls connecting the bottom and the upper deck portions would achieve the desired results. Likewise, any mattress or combination of mattress pieces that provide a bottom surface generally conforming to the shape of the step deck would achieve the desired results.
The movable deck head section is coupled to the intermediate frame and is configured to pivot relative to the weigh frame about an effective pivot axis positioned to lie above the lower deck portion. Preferably, the effective pivot axis is located generally adjacent to a pivot axis defined by the hip of a person lying on the sleeping surface in order to minimize the shear between the sleeping surface and the back of the person in the bed as the head section moves between the down position and the back-support position. To achieve this “reduced-shear pivot,” the head section is mounted to the weigh frame for both translational movement and pivoting movement relative to the weigh frame. The pivoting and translational movements combine to produce a motion in which the head portion pivots relative to the frame about the effective pivot axis.
The head section of the articulating deck can pivot relative to the intermediate frame between a down position generally parallel to the weigh frame and an upward back-support position. When a person on a sleeping surface moves from a flat position to a sitting position, the back and legs of the person engaging the sleeping surface lengthen. The reduced-shear pivot accommodates this lengthening to reduce the shear between the back and legs of the person and the sleeping surface as the head section pivots between the down position and the back-support position by expanding the deck and the sleeping surface. The reduced-shear pivot allows the upper body of the person on the sleeping surface to be tilted upwardly without moving the lower body of the person. This reduces the tendency of the person to slide relative to the sleeping surface during articulation of the head section, thereby reducing the shear between the back and legs of the person and the sleeping surface.
The step deck can also include an upper deck end portion adjacent to the foot end of the bed. The foot section can be coupled to the upper deck end portion for pivoting movement about a pivot axis that is positioned to lie above the lower deck. The foot section can also be configured to contract and expand to vary the length of the foot section as the foot section pivots about the pivot axis so that the foot section can pivot downwardly when the bed is in the low position to place the feet of the person supported on the sleeping surface on the floor. In addition, the foot portion of the mattress can be configured to shorten in conjunction with the contraction of the foot section. Also, the seat and foot portions of the mattress can automatically become thinner to maintain an appropriately sized seat area as the foot section pivots downwardly.
A pair of siderails can be provided on each side of the bed. Each pair of siderails includes a head section siderail that is movable with the pivoting head section of the deck and a body section siderail that is movable with the seat section. Each siderail is preferably maintained in a generally vertical orientation adjacent to the sides of the bed.
The siderails are each movable between an upward patient-restraining position restraining the movement of a person supported on the sleeping surface past the sides of the sleeping surface and a downward tucked position. When in the patient-restraining position, the bottoms of the siderails are positioned to lie above the upper deck side portions and the siderails abut the sides of the mattress. When in the tucked position, the tops of the siderails are positioned to lie beneath the upper deck side portions in a niche defined by the upper deck side portions and the side walls connecting the lower deck to the upper deck side portions.
When moving between the patient-restraining position and the tucked position, the siderails rotate outwardly and downwardly from the patient-restraining position away from the side of the bed, and then back inwardly and downwardly to the tucked position beneath the upper deck portion. The siderails trace the same path when moving from the tucked position to the patient-restraining position. The rotating mechanism, which holds the siderails in vertical orientations parallel to the side of the mattress through the entire range of movement, places the siderails against the sides of the mattress when the siderails are in the patient-restraining position, allowing for the provision of a narrower bed than would otherwise be provided, even though the mattress of the bed has a standard width.
The body section siderails are coupled to brackets that are fixed to the frame. The head section siderails are coupled to brackets fixed to the side wall of the deck. However, the bed may be provided with breakaway head section siderails, each head section siderail being mounted on a pivotable collateral deck section to move the siderail from the tucked position to a generally vertically downwardly extending down-out-of-the-way position, preferably extending downwardly along the head of the bed to provide clear access to space beneath the intermediate frame. Breakaway siderails provide the caregiver with even greater access to the space under the sleeping surface of the bed when the siderails are in the down-out-of-the-way position while also improving access across the sleeping surface for equipment that may be desired for use on a person on the sleeping surface.
The head section and body section siderails are configured to maintain a between-rail gap of approximately 2–3 inches as the head section siderail moves relative to the body section siderail. Also in preferred embodiments, the head section siderails are shorter than the body section siderails and shorter than typical siderails making it possible for a person to enter the bed from the side using the head section siderail as a support and to properly position their hip on the sleeping surface.
The bed can also be used to monitor the total weight of objects, including a person, carried by the bed. The bed is configured so that hospital equipment such as IV poles can be attached to the bed such that the weight of these items is not included in the weight monitored by the bed, thereby facilitating the convenient use of such equipment.
In this specification and in the claims, such terms as “chair bed,” “hospital bed,” “patient-care bed,” and “examination table” are used in a general sense and not in a limiting sense. The bed of the present invention has wide application and may be used in a variety of situations. The improvements disclosed herein may be used on beds in general, on medical tables, stretchers, gurneys, and so forth as appropriate. However, the bed of the present invention provides significant improvements in caregiver productivity and patient outcomes. The following capabilities are included in the bed of the present invention:                1. Full chair capability as a built-in feature, enabling a single caregiver to execute an order from a physician to place the person in a chair by operating controls to convert the bed into a chair while the patent is on the bed.        2. Infinitely adjustable head, thigh, and foot section angles that allow any desired position of the head, thigh, and foot section with in the range of movement of those sections.        3. Foot egress capability, enabling a single caregiver to transfer a person from the bed to a wheelchair or ambulate the patient.        4. Modular surface capability, allowing a single caregiver to adapt the mattress surface to provide decubitus prevention and pulmonary treatment capability as the needs of the person change.        5. In-bed weighing capability, enabling a caregiver to monitor the weight of a person on the sleeping surface.        6. Electric or manual Trendelenburg capability, allowing the sleeping surface to assume the Trendelenburg position having the feet of the person carried by the bed slightly elevated above the head. In addition, the sleeping surface can assume a reverse Trendelenburg position having the head of the person slightly elevated above the feet.        7. Reduced-shear pivot capability, causing the articulating sections to minimize shear forces between the sections and the person so that the person does not slide appreciably relative to the sleeping surface of the mattress as the articulating sections pivot.        8. Siderails having a one-handed release mechanism and that rotate outwardly and rotate from the patient-restraining position to a tucked position underneath the patient-restraining position.        9. Breakaway siderail capability, having a pin that can be removed from the foot end of each head section siderail after the siderail has been rotated under to the tucked position so that the foot end of the head rail pivots downwardly and toward the head end of the bed, thereby providing a caregiver with additional access to the sleeping surface, additional clearance around the deck so that the caregiver has improved access to the patient, and allowing for the insertion of a C-arm laterally further across the person than may be achieved without the breakaway siderail capability.        10. CPR foot pedal capability, enabling rapid movement of the head section from the upward sitting position to the horizontal CPR position by activation of a CPR pedal so that the caregiver has instantaneous control with one-step operation that requires constant activation.        11. Manual pump articulation and a battery for controlling the valves, allowing the caregiver to raise or lower the sleeping surface or the head, thigh, and foot sections of the articulating deck and allowing movement of the sleeping surface to the Trendelenburg position during remote operation of the bed when the bed is disconnected from external power sources.        12. In-bed X-ray capability including a radiolucent window and head and abdomen access for a separate C-arm of X-ray equipment allowing the caregiver to obtain X-rays of the head, chest, and abdomen without removing the person from the sleeping surface of the bed.        13. Four wheel braking capability for braking four caster wheels mounted to the base, the braking capability being activated by a butterfly wheel pedal that can move between a braking position, a neutral position, and a steering position that allows for the steering of the caster wheels during movement of the bed.        14. Mattress including pressure-reducing capability in the seat section when in the sitting position to reduce the chance of skin breakdown.        15. Mattress including a modular design so that several surfaces/air therapies are driven by a common air source, a common graphical caregiver interface, and a common distributed network, and so that a caregiver can install and initiate an air therapy without moving the person off of the original sleeping surface.        
The bed of the present invention includes a base frame or a main frame upon which several basic components are mounted such as the system displays and the air compressor for the various air-driven treatment technologies. The base frame provides various care modules which are mountable on the bed and usable with the control network, display, and air compressors built therein. Illustratively, a common air power source and handling unit is located on the main frame of the bed to supply air to all of several selected mattress surface therapies. Therapy frame header connectors including a plurality of air lines for coupling the air source to selected air surface modules is provided. A therapy surface control module is mounted on the bed. A microprocessor or microcontroller-based electronic module is configured to be electrically coupled to electronics residing in each of the separate treatment surface modules. The control module on the bed will control power, air distribution, and graphical display, and the control module contains valves and electronic controls to be described hereinafter. The control module is capable of recognizing the specific surface which is connected to the control module and will then control the air handling unit and display according to the selected surface.
The bed will primarily be powered from the main AC power input for the hospital or clinic in which it is installed. When disconnected from the main AC power input, a battery may be provided on the base frame for limited functionality.
The bed including the features described above meets the needs of multiple acute care areas including critical care, step down, medical/surgical, and subacute care. This flexibility results in reduced handling and transport of the person since mobility can be provided closer to the stretcher, and the person can stay on one bed for transport so that seamless care can be provided. In addition, convertibility of the bed to the sitting position provides benefits including that the upright position provides physiological benefits meeting M.D. orders, it minimizes handling of the person and minimizes the number of caregivers required for handling people, it speeds patient recovery, it minimizes the length of stay satisfying the critical pathway, and it enhances patient safety.